Cabbage farms in West Africa ravaged by the Diamondback Moth (DBM), Plutella xylostella, are set to make a strong comeback as IITA scientists in Benin Republic successfully develop and field test the use of a biopesticide based on Beauveria bassiana, a fungus, against the pest. For years, DBM has been devastating both smallholder and commercial cabbage farms in the region, affecting farmers’ incomes and market prices of the crop.
“From a disappointment, cabbage production now looks very promising with the use of B. bassiana,” says Raymond Ahinon, head of the Crop Department of the Songhai Center — a facility that specializes in training, production, and research-for-development of sustainable agricultural practices — in Porto Novo, Benin. “We have been using B. bassiana on our cabbage farms for some time now, and it has effectively kept DBM under check,” he adds.
Cabbage, and its cousin kale, are regarded as high-value cash crops. Compared to other vegetables such as carrot and lettuce, farmers say returns are higher with cabbage cultivation. Despite this, thous ands of farmers in West Africa had to ab andon cabbage production because of the destruction caused by DBM on their farms. Market prices for African cabbage have consequently jumped because of dwindling supplies.
The situation is worsened by the high costs associated with synthetic pesticide – farmers’ only recourse against DBM.
“The most common synthetic chemical pesticides used by farmers are bifenthrin and deltamethrin,” says Ignace Godonou, IITA Entomologist based in Benin. “About 19 applications of these chemicals are needed within three months of the crop’s growth prior to harvest. But the cost of these chemicals are oftentimes prohibitive for most farmers.”
Globally, chemical control is estimated at about US$1 billion annually, not counting the costs to human health and the environment related to its use.
Farmers like Louis Aw andjinou, who has been cultivating the crop since 1986, have observed that the chemical pesticides have been less and less effective against DBM over the years. Godonou explains that this is because the pest has developed resistance to a wide range of synthetic insecticides.
Alternatively, farmers have been using botanical pesticides, mostly seed extracts of the neem tree, against DBM and a wide range of other arthropod pests, but the success of this approach has been limited.
Godonou says that when used in an integrated pest management approach, B. bassiana offers a cost-effective solution for the sustainable control of DBM.
A study by Godonou et al published in the Crop Protection Journal in 2008 indicated that B. bassiana grows naturally in soils throughout the world, generally specific to target pests, persists in the environment, ecologically-friendly and easy to mass produce.
“With the ability to remain active on the field for several months after initial application, B. bassiana will end the rigor of repetitions and high costs and risks associated with the use of chemical pesticides,” Godonou adds.
A co-author of the study, C. Atcha-Ahowe, also an IITA scientist, says field trials of B. bassiana have sparked high dem and for it. “Many of the farmers who ab andoned cabbage cultivation because of DBM but who want to go back are requesting for B. bassiana , but the problem is the availability of the product,” he says.
Like Green Muscle® which was picked up by the private sector, Godonou is hopeful that B. bassiana would go the same route and be adopted by vegetable farmers across the continent.
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Pour plus d'informations, veuillez contacter :
Dr Ignace Godonou, i.godonou@cgiar.org
Entomologist
IITA-Bénin
Jeffrey T. Oliver, o.jeffrey@cgiar.org
Chargé de communication d'entreprise (international)
Godwin Atser, g.atser@cgiar.org
Chargé de la communication d'entreprise (Afrique de l'Ouest)
Bureau de la communication
IITA – Siège
Ibadan, Nigéria
À propos de l'IITA
L'Afrique fait face à des problèmes complexes qui pèsent lourdement sur l'agriculture et la vie des populations. Nous développons des solutions agricoles avec nos partenaires pour lutter contre la faim et la pauvreté. Nos recherches pour le développement (R4D), maintes fois récompensées, reposent sur une réflexion ciblée et autorisée, ancrée dans les besoins de développement de l'Afrique subsaharienne. Nous travaillons avec des partenaires en Afrique et au-delà pour réduire les risques pour les producteurs et les consommateurs, améliorer la qualité et la productivité des cultures, et générer de la richesse grâce à l'agriculture. L'IITA est une organisation internationale R4D à but non lucratif fondée en 1967, dirigée par un Conseil d'administration et soutenue principalement par le CGIAR.
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